Centrifugal exhaust-fan



Patented Feb. 3, 1920.

INVEN TOR.. Charlas /7. L 66 I A TTORNEY cnitritmcchn newsman:

Specification of Letters Patent.

Patented Feb. 3, 1920.

Application filed July 2, 1917. Serial No. 178,101.

To all whom it may concern:

Be it known that I, CHARLES M. LEE, a citizen of the United States,residing at Falls City, in the county of Richardson and State ofNebraska, have invented certain new and useful Improvements inCentrifugal Exhaust-Fans; and I do declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame, reference being had to the accompanying drawings, and to theletters and figures of reference marked thereon which form a part ofthis specification.

My invention relates to centrifugal exhaust fans, and more particularlyto a fan of that character employing a substantially cylindrical rotarymember, or fan wheel, comprising a plurality of parallel vanes solocated relative to each other that rotation of the fan willtangentially discharge air therefrom; the principal object of the invention being to provide a fan of this character adapted for use instores, mills, factories, etc., for ventilating, or other purposes,which is of simple and substantial construction, yet highly efficientand practically noiseless.

In accomplishing this object, I have provided improved details ofstructure, the preferred forms of which are illustrated in theaccompanying drawings, wherein:

Figure I is a perspective view of a fan constructed according to thepresent invention.

Fig. II is a side elevation of the same, shown in functional relation toan air shaft.

Fig. III is a transverse, sectional view of the fan wheel on the lineIII-III, Fig. II.

Referring more in detail to the drawings:

1 designates a rotary fan embodying the present invention, comprising along1tud1- nally arranged drive shaft 2, whlch 1s revolubly supportedadjacent its opposite ends by brackets 33' and is provided at one endwith a belt wheel 4 over which a belt 5 may operate to drive the fan.

Fixed to the shaft adjacent the belt wheel 4, is a head or drum 6, andmounted thereon and extending in parallel relation longitudinally alongthe shaft 2 are vanes 7, each of the latter being supported at its endopposite the drum 6 by brace rods 8, which are attached at their outerends to the forward edges of the vanes and at their inner ends to acollar 9 that is fixed on the shaft 2, and are spaced apart by bracerods 10, extending between adjacent edges of the vanes so that thelatter are held substantially rigid along the drive shaft.

Each of the vanes 7 comprises an oblong metal sheet, curved transverselyto present an outwardly facing convex surface, and is provided at oneend with an inturned flange 12 for receiving nails or bolts, whereby itmay be attached to the head 6; the vanes being mounted on the head withtheir forward, longitudinal edges located below and slightly back of therear edge of a forward blade, forming passages 13 therebetween, so thatas the wheel revolves forwardly air will be drawn from the interior ofthe cylinder and discharged tangentially from the vanes, tending tocreate a vacuum within the cylinder which creates a suction at the openend of the fan cylinder.

When in use, the open end of the fan wheel is located adjacent thedischarge or intake end of an air shaft 15, so that with the fanoperating in the direction indicated by the direction of the centralarrow (Fig. III), the tendency to create a vacuum within the cylindercauses a draft of air through the shaft; the force of the draft createdbeing dependent on the rate at which the fan is driven and itsdischarging capacity.

It is also apparent that by reversing the direction of rotation of a fanof this construction, a current of air may be forced into an air shaftinstead of being drawn therefrom.

Fans of this type are usually operated at high speed and it has beenfound that the present arrangement of blades efl'fects considerablehigher eliiciency than in those wherein the blades have the spiral formand produces a fan of great rigidity and stren h.

It is further apparent that the efiiciency of the fan may be increasedto a certain extent by an increase of the number of vanes, or by alengthening of the fan cylinder.

Having thus described my invention, what I claim as new therein, anddesire to secure by Letters-Patent, is:

A fan of the class described comprising a longitudinal drive shaft, ahead on said drive shaft, a plurality of vanes, each con- .nected at oneend to the head and extending longitudinally of said shaft to form a fancylinder, the forward longitudinal edge of each blade being spaced belowthe rear longitudinal edge of a preceding blade, braces connected to theshaft at points distant from the head, said braces being laterallydisposed and engaging the rear edges of the blades or vanes, andadditional braces adjacent to the first named braces, the additionalbraces being connected to the rear edge of one blade 01' vane and theforward end to an adjacent blade 01' vane.

In testimony whereof I allix in signature.

CHARLES LEE.

